JAN. — MAR. 1857.] PoJitograpUc Printing Process. 167 
300 grs. Muriate of Ammonia, 
240 grs. Sugar-candy. 
Float the paper on this for half a minute. Hang up and dry — 
Ironing this paper before sensitizing seems quite unnecessary. 
To sensitize use, 
60 grains Nitrate of Silver, 
12 minims Acetic Acid, 
1 oz. Dist. Water^ 
Float it on this for 4 or»5 minutes — hang up to dry. 
Expose in the pressure frame until the lights are a shade or two 
darker than they ought to be in the finished picture. When print- 
ed sufficiently — wash all traces of the aceto-nitrate out of the 
paper — in a darkened room. Dissolve ofi" the Albuminate of Sil- 
ver in a bath of Hyp. 1 to 8 of water, or of liquor Amm. 1 drachm 
to 1 pint of water, in the former about 8 minutes — in the latter the 
action is more violent and practice only will enable the operator to 
judge of the time. 
The Print must be well washed after this bath and then immers- 
ed in the toning bath composed of 
10 grains Chloride of Gold, 
30 oz. Distilled water, 
30 grains Hyposulph. Soda, 
30 minims of Hydrochloric acid if the chloride of Gold 
be neutral. 
Mix the Gold and the Hypo, each in 15 oz. of water, and pour 
the former into the latter gradually stirring the white. Then add 
the acid if necessary. 
Keep the picture in this, till the shades are a deep purple, and 
the lights, a pleasing grey. Then pass through water — (not for 
more than a minute or two as the lights are yellowed by longer 
washing,) into the second fixing bath of Hypo. 1 to 8 of water to 
ensure its perfect fixation. It should remain in this from ten to 
fifteen minutes, ^yash as usual. 
